WASHINGTON - Forty-eight police officers were killed in attacks while on duty in 2006 in the United States, seven fewer than the previous year, the FBI said Monday.

Forty-six of the officers were killed with guns. Two were killed with vehicles, the FBI said. Twelve of the officers were killed during arrests, and nine of them were ambushed, the FBI said as it released a report of preliminary statistics.

Another nine officers were killed in traffic chases or stops, and eight were killed while responding to disturbance calls. Six officers were killed while investigating a suspicious situation, and two were killed in "tactical situations," such as hostage situations. One officer was killed while handling a prisoner and another was killed while handling a "mentally deranged person," the FBI said.

Twenty-two of the killings were in the South; 11 were in the West; seven were in the Northeast; six were in the Midwest, and two were in Puerto Rico, the FBI said.

Another 66 officers died in accidents while on duty in 2006, the FBI said.